Remote reading flux valve compass system



Sept# 23, 1947- L.. F. BEACH 2,427,654

REMOTE READING FLUX VALVE. CQIIPASS SYSTEMV med umn 1s, 1945 FiG.I

Patented Sept. '23, 1947 UNITED STATES PATENT ortica REMOTE READING FLUX VALVE SYSTEM Lennox F. Beach, Pbrt washington, N. Y.,

signor to Purves Corporation,

COMPASS as Springfield,l

Mass., a corporation oi' Massachusetts originel application July 3o, 1940, sei-liu No. 348,582. Divided and this application March 15,v 1943, seria1Nc.479,2s7

17 claims. 1

direction of the eld and circuits for utilizing these potentials to actuate indicating or power controlling devices.

The present invention is a division of my co-l pending application Serial No. 348,582, illed in the United States Patent Olce on July 30, 1940, which became Patent No. 2,383,459.

In U. S. Patent 2,047,609, issued to Haig Antranikian, July 14, 1936, there is disclosed a method of measuring the direction and intensity of asteady or slowly varying magnetic i'leld by applying to an inductor member or members of magnetically permeable material carrying the flux of the ileld, a magneto-motive force induced by periodically varying direct current in a primary or exciting winding. This magneto-motive force being added to the ield magneto-motive force produces a distorted alternating iiux wave in which peaks in one direction are cut oil or flattened due to the non-linear magnetic characteristic of the inductor material, the amount of distortion varying with the intensity of the steady iield.

Such distortion of a ilux wave is commonly explained on the basis of saturation" of the iron,

or other permeable material. However, it should be noted that distortion may be of different degrees depending on the portion of the magnetization curve covered and it is not necessary in all cases that complete saturation be attained in order to detect or measure a steady eld.

According to the present invention an improved type ci' inductor is provided and by the use of an alternating or pulsating exciting magneto-motive force of suitable magnitude, a measure of the steady magnetic bias produced in the inductor by the iield is obtained whether or not the inductor becomes completely saturated A measuring system without the rotating inductor of the well known inductor compass is thus provided which may, in one form. 'be adapted to provide remote indications of the direction of a iield by simultaneously measuring a plurality of components of the ileld and utilizing them in an indicating system similar to a Selsyn transmission system in which the remote indicating E 2 device vectorially combines the components to reproduce the direction of the original ieid. As adapted to compass indication, the horizontal component of the earths field is the vector whose 5 direction is reproduced.

mote indicating system responsive to the direction of a magnetic eld which employs a sensi- -tive pick-up device or transmitter without a rotating inductor member.

Another object is tc provide a system for supplying a plurality of electrical potentials proportional, respectively, to components of a magnetic iield for actuating a direction indicating instrument of the Selsyn type.

Another object is to provide a system in which alternating potentials proportional to a magnetic iield or components thereof are produced by periodically varyingV the magneticproperties of a permeable member or members by stationary means.

Still another object is to provide a remote indicating compass system having the advantages of direction indicating systems of the aforementioned types.

Other objects and advantages will become apparent as the description proceeds.

Referring tc the drawings,

Fig. 1 is a schematicdiagram of an indicating system employing a Selsyn type indicator.

Fig. 2 is a modification of the system of Fig. 1.

In the modification shown in Fig. 1, a plurality of permeable cores or inductors is employed to 'generate potentials proportional to components of a magnetic eld. As an illustration,`Fig. 1 shows a core structure or inductor of permeable magnetic material which comprises three core legs i, 2 and 3 positioned at angles of 120 with one another for measuring the components of the 40 neld in the directions ,of their respective axes.

These core legs orinductors may be in the form of straight bars as shown in the aforementioned Patent 2,047,609,7701' preferably in the improved form shown in Fig. 2 and more particularly illustrated and described in said Letters Patent No.

2,383,459, above referred to. The latter `form of inductor provides substantially closed magnetic circuits tor the exciting flux, which, in addition to advantages pointed out in the above patent in connection with similar i'orms of magnetic circuits, renders the device insensitive to extrane- One object of the invention is to provide a reous alternating fields. The core legs or inductors, I, 2 and 3 each have symmetrically located exciting windings as for example 4 and 5 on inductor B and 1 on inductor 2 and 8 and 9 on inductor 3, all the exciting windings being connected to A. C. source I0. In addition, the three core legs have pick-up windings Il, I2 and I3, respectively, which are shown as being Y connected, the outer terminals of the Y being connected'to'conductors I4, I5 and I6 of a transmission line.' The' voltage wave induced in each of the pick-up windings under the inuence of an external magnetic eld will be of a frequency double that of the source l0. Since the voltages across the three lines i4, I5 and I6 are proportional to three symmetrical components of the magnetic field they may be utilized to reproduce the direction of the eld at a distant point as is done in the usual type of Selsyn system and for this purpose a Selsyn receiver |1 comprising" a polycircuit stator herein illustrated as having three windings I8, I9 and 20, and a single-phase rotor winding 2| is shown; Winding 2| is supplied with current of twice the frequency of sup.- ply I0 through frequency doubler 22 and owill therefore align its axis with the resultant of the three component fields due to the currents in the three stator windings. If needed, means" for adjusting the phase of the output of doubler 22 may b'e provided. There is shown connected to rotor winding 2| a compass card 23, readable by means of an index 24 to indicate the direction of the field to which the transmitter is subjected. It will be understood that by rigidly connecting rotor 2| to a power driven object which is to be aligned in the direction of the magnetic field, receiver I1 may also be utilized as a Selsyn signal generator to generate a voltage'proportional to the misalignment of said object with the eld for controlling the driving means as is well known in the art of positional control systems employing Selsyn type receivers. v

The circuit of the frequency doubler 22 is similar to a known full wave rectifier circuit except that the double frequency A. C, ripple is utilized as the output, the D. C. component in this case being blocked by condensers 25 and 26. Obviously, any type of frequency doubler may be employed.

While for purposes of illustration, there is shown in the drawings a remote control system which depends upon resolving the magnetic field at the transmitter into three components, the plurality of field components referred to is not limited to three, instruments being known for utilizing `other numbers of components, for example', two rectangular components.

VIt will be apparent that the improved inductor shown and described in my said co-pending application Serial No. 348,582; is particularly suitable as an element in a transmitter in a remote indicating system of the types above described. Such use of this inductor in a three component transmitter is illustrated in Fig. 2.

In this gure three inductors 21, 28 and 29, each similar in construction to the inductor described in my co-pending application above referred to, are symmetrically arranged as a transmitter and their pick-up or secondary windings 30, 3| and 32 are connected to Selsyn receiver I 1, as in Fig.v 1. For simplicity the connections of the exciting windings to the A. C. source are omitted.

The inductors of the present invention are preferably formed of permeable ferrous alloys such as permalloy, hypernik and the like. Certain of these alloys are particularly useful in practicing the present invention since their magnetization curves have sharper breaks than the curve for iron, and so provide a. sudden transition from a non-saturated to a saturated or nearly saturated condition, which is an aid in securing sensitivity.

Also, while the description refers chiefly to the use of exciting M. M. F.s due to alternating currents. it will be understood that any periodically varying exciting current including pulsating direct current may be employed to produce these M. M. F.s since a pulsating direct current has an alternating component or components, the steady component merely supplying an additional biasing M. M. F.

The present invention, among other important applications, is particularly adapted to be used as a remote indicating compass on moving vehicles, for example, aircraft, where the simple, compact and rugged construction of the inductor pick-up due tothe absence of moving parts and the fact that it is unaffected by acceleration or vibration is of great importance. Another advantage is the ability to locate the pick-up in thatpart of the craft least affected by disturbing magnetic fields and actuate from it an indicator or a plurality of indicators in suitable locations, no care being required to maintain the pick-up in operative condition. Where multiple indicators are used, amplifying means may be inserted in the transmission line if necessary to supply more power than can be taken from the pick-up. Also with a single or with multiple indicators an amplifier may be used to prevent reaction of the indicator or indicators on the pick-up.

It will be further understood that in any of the forms of the invention employing remote indicators, such indicators may be oriented initially to position the stationary coils thereof in suitable relationship to the axes of the inductors of the pick-up. Y

As many changes could be made in the above construction and many apparently widely different 'embodiments of this invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. In a remote reading compass comprising a plurality of relatively angularly disposed inductors, coil means for producing an alternating flux in said inductors when connected to a source of alternating current energy, a source of alternating current energy connected thereto, pick-up coils associated with each of said inductors for generating potentials under the influence of an external magnetic eld, moto' means comprising a stator and rotor, said stator having a polycircuit Winding connected in polycircuit relation with said pick-up coils and said rotor having a single phase winding, means including a frequency doubler for exciting said rotor winding from said source of energy, and indicating means associated with said rotor.

2. A remote reading compass of the earth inductor type, comprising a plurality of inductors positioned at equiangles to each other, primary and secondary coils on each, an A. C. supply, said primary coils being excited in phase from said supply, a motor of theV A. C. self-synchronous acme v -current, said primarycoils being connected to said current source for producing periodically varying fluxes in said inductors. said secondary coils being adapted to generate potentials under the iniiuence of an external unidirectional magnetic iield, motor means comprising a stator and rotor, said lstator having a polycircuit winding connected in polvcircuit relation with said secondary coils, the windings oi said stator being respectively connected with correspondingly disposed secondary coils and saidrotor having a single phase windnents of the earths magnetic Aiield, an vit. C.,

source, means connected to said source for producing substantially equal alternatinguxes in two portions of each of said core strips respectively owing in opposite directions at a given instant, said fluxes alone neutralizing one another u but producing a varying resultant in-combinati'on with the flux of the eld, said resultant flux having a component el double the frequency ofv said source and proportional to the component ol' the earths neld along the axis of the core strips, means electrically asociated with said core strips for producing potentials proportional to said several double frequency alternating iiux componente, an indicator including electromagnetic means for receiving said several potentials and for creating therefrom a magnetic eld having the direction of the original eld, an electromagnet rotatable in said field, means for exciting said magnet with A. C. oi double the frequency of said source, and a transmission line connecting said core assembly and said indicator.

d. A system forthe remote indication of the direction of a magnetic eld comprising three symmetrically positioned l inductors each comprising an elongated core of permeable magnetic material, nux collectors extending laterally from the ends of said inductors, coil means surrounding each of said inductors for applying a periodically varying exciting magneto-motive force for circulating exciting flux through a portion of each of said cores and through one of the ux collectors associated with each, coil means also surrounding each of said inductors for lapplying a second periodically varying exciting magnetomotive force for circulating an instantaneously equal and opposite exciting ux through -another portion of each of said cores and the other of the ux collectors associated with each,\a source of periodically varying current connected with both of said coil means and a pluralityof means electrically associated respectively with each of said cores for producing electro-motive forces responsive to variations of the resultant fluxes in said cores, said resultant uxes being due to the non-linear combination in the cores of the field ilux and the exciting iiuxes, a polycircuit transmission line connected to said electromotive forcee producing'means, a remote `indicator of the selfsynchronous type having field windings corresponding in number and space disposition to said electromotive force-producing means and connected in said transmission line to receive the severalE. M.F.s of saidE. M, F. producing means, corresponding electro-motive force-producing means and ileld windings being interconected to thereby indicate the direction of the iield, and means for exciting the rotor winding of said indicator with alternating current of the same frequency as said transmitted E. M. F.'s.

5. In a remote reading compass comprising a plurality of relatively angularly disposed inductors, primary and secondary coils on each of said inductors, a source of periodically varying ing polycircuit relation to said pick-up coils andl ingfand means including a frequency doubler connected with said current source for exciting said rotor winding.

6. A remote reading compass system comprising a iiux valve including an inductor having a, plurality oi' relatively angularly` disposed core legs of permeable magnetic material, a ,source of periodically varying current, coil means connected with said source and surrounding said core legs for producing a, periodically varying ilux in said core legs, pick-up coils associated with each of said core legs and connected in polycircuit fashion for generating potentials under the iniluence of an external magnetic iield, and an indicator in' cluding stator windings connected in corresponda rotor winding connected with said source of current.

7. A remote reading compass system comprising a nux valve including an inductor having a plurality of relatively angularly disposed core legs of permeable magnetic material, a source of-period ically varying current, coils means connected with said source and associated with said inductor for producing a periodically varying iiux in said core legs, pick-up coils associated with each of said I core legs and connected in polycircuit fashion for generating potentials under the iniiuence of an external magnetic iield, an inductive device comprising stator windings connected in corresponding polycircuit relation to said pick-up coils and a rotor winding, and means for exciting said rotor winding with current of the same frequency as that of said potentials generated in said pick-up coils.

8. In a magnetic compass system, a iiux valve comprising a core of permeable magnetic material having a plurality of relatively angularly disposed legs, adapted to be disposed horizontally in the earths magnetic iield, coil means associated with said core and-adapted to be connected with a source of periodically varying current for producing periodically varying uxes in said core legs, a pick-up coil associated with each core leg for generating pbtentials under the`innuence of said external magnetic eld, s aid pick-up coils being interconnected in polycircuit fashion, a receiver having a stator comprising a polycircuit winding electrically connected in polycircuit fashion to said pick-up coils, a rotor and a winding therefor connected with a source of current having the same frequency as the output of said pickup coils, and a compass card turned with said rotor to reproduce the orientation of said core in said iield.

9. In a system of the character described, a. ux valve comprising a core of permeable magnetic material, coil means lassociated with said core'and adapted to be connected to a source of periodically varying current for ,producing periodically varying iluxes in said core, a plurality of pick-up coils associated with relatively angularly disposed portions of said core for generating potentials under the influence of an external mag- 1- netic field, said pick-up coils being interconnected in polycircuit fashion, a receiver having a'stator comprising a polycircuit winding electrically connected in polycircuit fashion to said pick-up coils, and a rotor having a winding connected with a. source of current having the same frequency as the outputs of said pick-up coils.

10. In a system of the lcharacter described, a

fluxr valve comprising a core of permeable mag-` in polycircuit fashion, a receiver having a stator comprising a polycircuit winding electrically connected in polycircuit fashion to said pick-up coils, and a rotor having a winding connected with said source of current.

11. An electrical inductive device for produc: ing through interaction with a unidirectional magnetic field a three-circuit, variable alternating potential output and in which the alternating E. M. F. in each circuit varies with the orientation of the device in the magnetic eld, said device comprising an inductor having three core legs of permeable magnetic material angularly disposed with respect to one another, coil means associated with said inductor and adapted to be connected with a source of single phase alternating current for producing periodically varying fluxes in said core legs, and a pickup coil associated with each core leg for generating varying potentials under the influence of said external field upon said core legs, said pick-up coils being Y-connected in a. three-circuit alternating output similar to that of a Selsyn transmitter, and a receiver having a polycircuit winding connected in polycircuit. fashion to the output of said inductive device.

12. An electrical inductive device for producing through interaction with a unidirectional magnetic field a three-circuit, variable alternating potential output and in which the alternating E. M. F. in each circuit varies with the orientation of the device in the magnetic eld, said device comprising an inductor having three substantially coplanar core legs of permeable magnetic material equi-angularly disposed with respect to one another, coil means associated with said core legs and adapted to be connected with a source of single phase alternating current for producing periodically varying fluxes in said core legs, and a pickup coil associated with each core leg for generating varying potentials under the inuence of said external field upon said inductor, said pickup coils being Y-connected in a threecircuit alternating output similar to that of a Selsyn transmitter, and a receiver ofthe Selsyn type having a polycircuit winding connected in polycircuit fashion to the output of said inductive device.

13. An electrical inductive device for producing through interaction with a unidirectional magnetic field a three-circuit, variable alternating potential output and in which the alternating E. M. F. in each circuit varies with the orientation of the device in the magnetic field, said device comprising an inductor having three core legs of permeable magnetic material equi-angularly disposed .with respect to one another in triangular fashion, coil means associated with Selsyn transmitter, and a, receiver ofthe Selsyn I 8 said inductor and adapted to be connected with a source of single phase alternating current for producing periodically varying fluxes in said core legs, and a pick-up coil associated with each core leg for generating varying potentials under the influence of said external field upon said inductor, said pickup coils being Y-connected in a threecircuit alternating output similar' to that of a type connected to the output of saidcoils, said receiver being powered by a source double the frequency of said rst source.

14. An electrical inductive device for producing through interaction with a unidirectional magnetic field a three-circuit, variable alternating potential output and in which the alternating E. M. F. in each circuit varies with the orientation of the device in the magnetic iield, said device comprising an inductor having three core legs of permeable magnetic material equi-angularly disposed with respect to one another in triangular fashion, coil means associated with said inductor and adapted to be connected with a source of single phase alternating current for producing periodically varying iluxes in said core legs, and a pickup coil associated with each core leg for generating varying potentials under the influence of said external iield upon said inductor, said pickup coils being Y-connected in a threecircuit alternating output similar to that of a Selsyn transmitter, and a receiver having a polycircuit Winding electrically connected in polycircuit fashion to the output of said inductive device.

15. A remote reading compass of the earth inductor type comprising an inductor of permeable magnetic material having three core leg's positioned at equiangles to each other, coil means associated with said inductor for producing, when excited from an A. C. supply, a, flux in said core legs, pick-up coils on each core leg, a motor of the self-synchronous type having its polycircuit windings connected in polycircuit relation and respectively with corresponding pick-up coils on said core legs, frequency doubling means connected with said A. C. supply for supplying exciting current to the rotor winding of said motor, and indicating means operable by said rotor.

16. In a remote reading compass system, a flux valve comprising an inductor of permeable magnetic material having a, plurality o1' relatively angularly disposed core legs, a source of periodically varying current, coil means associated with said inductor and connected with said source for producing a periodically varying flux in said core legs, a pick-up coil associated with each core leg for generating potentials under the influence of an external magnetic ileld, and indicating means including a polycircuit stator winding electrically connected in polycircuit fashion with said pick-up coilsto produce a resultant ileld dependent in direction upon the relationship of the external field to said inductor, and a rotor having a winding connected with said current source, said rotor being arranged in electrically cooperable (References on following page) 9 A1o REFERENCES CITED Number Name Date The following references are of record in the Pierre Sept,- 1' 1336 le of this patent: l J tuart oct' 31) 1 2,360,851 Curry Oct. 24, 1944 UNITED STATES PATENTS 5 2,374,166 Beach et al Apr. 24, 1945 Number Name Date FOREIGN PATENTS 2,240,680 Stuart May 6, 1941 Number Country Date 2,313,682 Stuart Mar. 9, 1943 451,850 Great Britain Aug. 10, 1936 118.21970 Bechberger Dec. 9, 1941 10 '183,731 France Apr. 15, 1935 2,047,609 Antranikian July 14, 1936 98,414 Sweden Mar. 1 9, 1940 

